Use of a transparent plastic film as a substrate of a display (e.g., liquid crystal display or electroluminescence (EL) display) has been studied in order to implement a display that has a reduced thickness, reduced weight, and flexibility.
However, since a plastic film generally allows water vapor, oxygen, and the like to pass through as compared with a glass substrate, the elements provided in a display may easily deteriorate when a transparent plastic film is used as a substrate of a display.
In order to solve the above problem, Patent Document 1 proposes a flexible display substrate in which a transparent gas barrier layer formed of a metal oxide is stacked on the surface of a transparent plastic film using a deposition method, an ion plating method, a sputtering method, or the like.
However, since excessive heat is applied to the plastic substrate when using the method disclosed in Patent Document 1, the optical properties of the plastic substrate may be adversely affected, and a deterioration in transparency may occur.
The above problem may be solved using a transfer laminate that includes a gas barrier layer. For example, Patent Document 2 discloses a method that includes forming a hard coat layer on a heat-resistant support, forming a gas barrier layer on the hard coat layer to obtain a transfer laminate, bonding a base formed of a polymer material to the gas barrier layer of the transfer laminate through an adhesive, and removing the heat-resistant support to obtain a liquid crystal display plastic substrate in which the gas barrier layer and the hard coat layer are stacked on the base formed of a polymer material.
Patent Document 3 discloses a plastic liquid crystal panel transfer foil in which at least one of a hard coat layer and a gas barrier layer and an adhesive layer are sequentially formed on a base film either directly or through a release layer. Patent Document 3 also discloses a method that produces a plastic liquid crystal panel by transferring the transfer foil to a plastic substrate using a heat transfer method.
However, the transfer laminates disclosed in Patent Documents 2 and 3 have a problem in that the gas barrier layer may be removed from the adhesive layer, or blisters or lifting may occur between the gas barrier layer and the adhesive layer when the transfer laminate is rolled (curved) or bent. Moreover, lifting may occur at the interface between the adhesive layer and the adherend (e.g., plastic substrate), and the transfer laminate may be removed from the adherend when the transfer laminate is bonded to the adherend, and subjected to high-temperature/high-humidity conditions.